Wavelength selective switch, single board, device, system, and method for transmitting optical signal

Abstract

A wavelength selective switch, a single board, a device, a system, and a method for transmitting an optical signal, which relate to the technical field of optical communication. The wavelength selective switch comprises a first output port, a plurality of first input ports, a first optical switching engine, a dispersion module, and a second optical switching engine. The second optical switching engine comprises a first area and a second area, the first area comprises a plurality of first sub-areas, and the width of the second area is greater than or equal to 2.5 times of the size of a light spot. The first optical switching engine deflects, by a first angle, a plurality of first single-wavelength optical signals inputted by the plurality of first input ports. The dispersion module transmits first parts of the plurality of first single-wavelength optical signals to the plurality of first sub-areas, and transmits second parts of the plurality of first single-wavelength optical signals to the second area. A plurality of first parts are reflected on the plurality of first sub-areas back to the dispersion module. The dispersion module combines the plurality of first parts into a first multi-wavelength optical signal and transmits the first multi-wavelength optical signal to the first output port. According to the wavelength selective switch of the present application, signal crosstalk can be avoided.

Description

Wavelength selective switch, board, device, system and method for transmitting optical signals

[0001] This application claims priority to the Chinese patent application with application number 202311249852.X filed on September 26, 2023, entitled “Wavelength selective switch, board, device, system and method for transmitting optical signals”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical communication technology, and in particular to a wavelength selective switch, a board, a device, a system, and a method for transmitting optical signals. Background Art

[0003] With the development of optical communication technology, optical switching equipment that uses optical signals for communication is becoming more and more widely used. For example, the optical switching equipment may be a reconfigurable optical add-drop multiplexer (ROADM).

[0004] A wavelength selective switch (WSS) is a key component of a ROADM. It has multiple first input ports and a corresponding first output port. The WSS transmits a portion of a first single-wavelength optical signal input from each first input port to the first output port, thereby attenuating the signal power.

[0005] The WSS further includes multiple second input ports. The WSS may transmit part of the second single-wavelength optical signal input from each second input port to the first output port, resulting in crosstalk between the two signals at the first output port.

[0006] Summary of the Invention

[0007] This application provides a wavelength selective switch, board, device, system, and method for transmitting optical signals to avoid signal crosstalk. The technical solution is as follows:

[0008] In a first aspect, the present application provides a wavelength selective switch, comprising a first output port, multiple first input ports corresponding to the first output port, a first optical switching engine, a dispersion module, and a second optical switching engine. The second optical switching engine comprises a first region and a second region, the first region and the second region being adjacent to each other. The first region comprises multiple first sub-regions corresponding to the first output port, and the width of the second region is greater than or equal to 2.5 times the optical spot size. The multiple first input ports are configured to transmit multiple first single-wavelength optical signals to the first optical switching engine, each of which comprises a first portion and a second portion. The first optical switching engine is configured to deflect the multiple first single-wavelength optical signals at a first angle and transmit them to the dispersion module. The dispersion module is configured to transmit the first portion of the multiple first single-wavelength optical signals deflected at the first angle to the multiple first sub-regions, and transmit the second portion of the multiple first single-wavelength optical signals deflected at the first angle to the second region. The first portion of the multiple first single-wavelength optical signals deflected at the first angle is reflected back to the dispersion module from the multiple first sub-regions, and the optical spot size is equal to the optical spot size of each first single-wavelength optical signal in the direction of the port. The dispersion module is further configured to combine the first portion of the reflected first single-wavelength optical signals into a first multi-wavelength optical signal, and transmit the first multi-wavelength optical signal to the first output port.

[0009] Because the width of the second region is greater than or equal to 2.5 times the spot size, which is equal to the spot size of each first single-wavelength optical signal in the port direction, the dispersion module transmits the second portions of the multiple first single-wavelength optical signals to the second region without reflecting the second portions of the multiple first single-wavelength optical signals. Consequently, the dispersion module does not combine the second portions of the multiple first single-wavelength optical signals into a single multi-wavelength optical signal, and thus does not transmit the multi-wavelength optical signal to any output port of the wavelength selective switch other than the first output port, thereby avoiding signal crosstalk.

[0010] In one possible implementation, the wavelength selective switch further includes: a second output port and multiple second input ports corresponding to the second output port; the second optical switching engine further includes a third region, the third region being adjacent to the second region, the second region being located between the first region and the third region, and the third region including multiple second sub-regions corresponding to the second output port. The multiple second input ports are configured to transmit multiple second single-wavelength optical signals to the first optical switching engine, each second single-wavelength optical signal comprising a third portion and a fourth portion. The first optical switching engine is further configured to deflect the multiple second single-wavelength optical signals at a second angle and transmit them to a dispersion module, where the first angle and the second angle are different. The dispersion module is configured to transmit the third portion of the multiple second single-wavelength optical signals deflected at the second angle to the multiple second sub-regions, transmit the fourth portion of the multiple second single-wavelength optical signals deflected at the second angle to the second region, and reflect the third portion of the multiple second single-wavelength optical signals deflected at the second angle back to the dispersion module from the multiple second sub-regions. The dispersion module is further configured to combine the reflected third portion of the multiple second single-wavelength optical signals into a second multi-wavelength optical signal and transmit the second multi-wavelength optical signal to the second output port. In this way, the first output port and the second output port share the second area, thereby improving the space utilization of the second optical switching engine and reducing the size of the second optical switching engine.

[0011] In another possible implementation, the wavelength selective switch further includes a third optical switching engine, a third output port, and multiple third input ports corresponding to the third output port. The first output port and the multiple first input ports belong to a first port group, the third output port and the multiple third input ports belong to a second port group, the first port group and the second port group are arranged relative to each other, and the second region includes multiple third sub-regions corresponding to the third output ports. The multiple third input ports are configured to transmit multiple third single-wavelength optical signals to the third optical switching engine, each of the third single-wavelength optical signals including a fifth portion and a sixth portion. The third optical switching engine is configured to deflect the multiple third single-wavelength optical signals by a third angle before transmitting them to the dispersion module, where the first angle and the third angle are different. The dispersion module is configured to transmit the fifth portion of the plurality of third single-wavelength optical signals deflected at the third angle to the plurality of third sub-areas, and to transmit the sixth portion of at least one third single-wavelength optical signal to at least one first sub-area, wherein the plurality of first sub-areas include the at least one first sub-area. The plurality of third single-wavelength optical signals deflected at the third angle include the at least one third single-wavelength optical signal. The fifth portion of the plurality of third single-wavelength optical signals deflected at the third angle is reflected back to the dispersion module from the plurality of third sub-areas, and the sixth portion of the at least one third single-wavelength optical signal is reflected back to the dispersion module from the at least one first sub-area. The dispersion module is further configured to combine the reflected fifth portion of the plurality of third single-wavelength optical signals into a third multi-wavelength optical signal and transmit the third multi-wavelength optical signal to the third output port, and to combine the reflected sixth portion of the at least one third single-wavelength optical signal into a fourth multi-wavelength optical signal and transmit the fourth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch. Because the second area includes the plurality of third sub-areas corresponding to the third output port, the space utilization of the second optical switching engine is improved.

[0012] In another possible implementation, the first offset in the dispersion direction between the center of the i-th first sub-region and the center of the i-th third sub-region is greater than or equal to 0 and less than or equal to the sum of the widths of 20 first sub-regions, i = 1, 2, 3, ..., K, where K is the number of the multiple first sub-regions.

[0013] In another possible implementation, the wavelength selective switch further includes a combiner and a deflection unit. The first optical switching engine is configured to transmit the multiple first single-wavelength optical signals deflected by a first angle to the combiner. The third optical switching engine is configured to transmit the multiple third single-wavelength optical signals deflected by a third angle to the deflection unit. The deflection unit is configured to deflect the multiple third single-wavelength optical signals transmitted by the third optical switching engine to the combiner. The combiner is configured to transmit the multiple first single-wavelength optical signals transmitted by the first optical switching engine and the multiple third single-wavelength optical signals deflected by the deflection unit to the dispersion module. In this way, the second offset in the dispersion direction between the i-th first single-wavelength optical signal and the i-th third single-wavelength optical signal can be reduced by the combiner, thereby reducing the first offset in the dispersion direction between the center of the i-th first sub-region and the center of the i-th third sub-region, so as to reduce the width of the second optical switching engine.

[0014] In another possible implementation, a second offset in the dispersion direction between the i-th first single-wavelength optical signal and the i-th third single-wavelength optical signal transmitted by the combiner to the dispersion module is constrained by a first offset, where the first offset is the offset in the dispersion direction between the center of the i-th first sub-region and the center of the i-th third sub-region, where i=1, 2, 3, ..., K, where K is the number of the multiple first sub-regions.

[0015] In another possible implementation, the wavelength selective switch further includes: a lens; a beam combiner configured to transmit the multiple first single-wavelength optical signals transmitted by the first optical switching engine and the multiple third single-wavelength optical signals deflected by the deflection unit to the lens; and a lens configured to transmit the multiple first single-wavelength optical signals and the multiple third single-wavelength optical signals transmitted by the beam combiner to the dispersion module. Because the beam combiner is located between the lens and the first optical switching engine, the first multi-wavelength optical signals and the third multi-wavelength optical signals transmitted by the beam combiner share the lens. This eliminates the need for a lens between the deflection unit and the dispersion module, thereby reducing the cost of the wavelength selective switch.

[0016] In a second aspect, the present application provides a method for transmitting optical signals, the method being applied to a wavelength selective switch. The wavelength selective switch comprises: a first output port, multiple first input ports corresponding to the first output port, a first optical switching engine, a dispersion module, and a second optical switching engine. The second optical switching engine comprises a first region and a second region, the first region and the second region being adjacent to each other. The first region comprises multiple first sub-regions corresponding to the first output port, and the width of the second region is greater than or equal to 2.5 times the spot size. In the method, the multiple first input ports transmit multiple first single-wavelength optical signals to the first optical switching engine, each of which comprises a first portion and a second portion. The first optical switching engine deflects the multiple first single-wavelength optical signals at a first angle and transmits them to the dispersion module. The dispersion module transmits the first portion of the multiple first single-wavelength optical signals deflected by the first angle to the multiple first sub-regions, and transmits the second portion of the multiple first single-wavelength optical signals deflected by the first angle to the second region. The first portion of the multiple first single-wavelength optical signals deflected by the first angle is reflected back to the dispersion module from the multiple first sub-regions, with the spot size equal to the spot size of each first single-wavelength optical signal in the direction of the port. The dispersion module combines the first part of the reflected multiple first single-wavelength optical signals into a first multi-wavelength optical signal, and transmits the first multi-wavelength optical signal to the first output port.

[0017] Because the width of the second region is greater than or equal to 2.5 times the spot size, which is equal to the spot size of each first single-wavelength optical signal in the port direction, the dispersion module transmits the second portions of the multiple first single-wavelength optical signals to the second region without reflecting the second portions of the multiple first single-wavelength optical signals. Consequently, the dispersion module does not combine the second portions of the multiple first single-wavelength optical signals into a single multi-wavelength optical signal, and thus does not transmit the multi-wavelength optical signal to any output port of the wavelength selective switch other than the first output port, thereby avoiding signal crosstalk.

[0018] In one possible implementation, the wavelength selective switch further includes: a second output port and multiple second input ports corresponding to the second output port; the second optical switching engine further includes a third region, the third region being adjacent to the second region, the second region being located between the first region and the third region, and the third region including multiple second sub-regions corresponding to the second output ports. The multiple second input ports transmit multiple second single-wavelength optical signals to the first optical switching engine, each second single-wavelength optical signal including a third portion and a fourth portion. The first optical switching engine deflects the multiple second single-wavelength optical signals at a second angle and transmits them to a dispersion module, where the first angle and the second angle are different. The dispersion module transmits the third portion of the multiple second single-wavelength optical signals deflected at the second angle to the multiple second sub-regions, and transmits the fourth portion of the multiple second single-wavelength optical signals deflected at the second angle to the second region. The third portion of the multiple second single-wavelength optical signals deflected at the second angle is reflected back to the dispersion module from the multiple second sub-regions. The dispersion module combines the reflected third portion of the multiple second single-wavelength optical signals into a second multi-wavelength optical signal and transmits the second multi-wavelength optical signal to the second output port. In this way, the first input port and the second input port share the second area, thereby improving the space utilization of the second optical switching engine and reducing the size of the second optical switching engine.

[0019] In another possible implementation, the wavelength selective switch further includes a third optical switching engine, a third output port, and multiple third input ports corresponding to the third output port. The first output port and the multiple first input ports belong to a first port group, the third output port and the multiple third input ports belong to a second port group, the first port group and the second port group are arranged relative to each other, and the second region includes multiple third sub-regions corresponding to the third output ports. The multiple third input ports transmit multiple third single-wavelength optical signals to the third optical switching engine, each of which includes a fifth portion and a sixth portion. The third optical switching engine deflects the multiple third single-wavelength optical signals at a third angle and transmits them to the dispersion module, where the first angle and the third angle are different. The dispersion module transmits the fifth portion of the plurality of third single-wavelength optical signals deflected at the third angle to a plurality of third sub-areas, and transmits the sixth portion of at least one third single-wavelength optical signal to at least one first sub-area. The plurality of first sub-areas include at least one first sub-area. The plurality of third single-wavelength optical signals deflected at the third angle include the at least one third single-wavelength optical signal. The fifth portion of the plurality of third single-wavelength optical signals deflected at the third angle reflects back to the dispersion module from the plurality of third sub-areas, and the sixth portion of the at least one third single-wavelength optical signal reflects back to the dispersion module from the at least one first sub-area. The dispersion module combines the reflected fifth portion of the plurality of third single-wavelength optical signals into a third multi-wavelength optical signal and transmits the third multi-wavelength optical signal to the third output port. The dispersion module also combines the reflected sixth portion of the at least one third single-wavelength optical signal into a fourth multi-wavelength optical signal and transmits the fourth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch. Because the second area includes the plurality of third sub-areas corresponding to the third input port, the space utilization of the second optical switching engine is improved.

[0020] In a third aspect, the present application provides a single board comprising: at least one wavelength selective switch according to the first aspect or any possible implementation of the first aspect.

[0021] In a fourth aspect, the present application provides an optical switching device, comprising a plurality of boards, at least one of the plurality of boards being the board described in the third aspect.

[0022] In a possible implementation, the optical switching device is a reconfigurable optical branching multiplexer.

[0023] In a fifth aspect, the present application provides an optical network system, comprising: a plurality of optical switching devices, at least one of the plurality of optical switching devices being the optical switching device described in the fourth aspect or any possible implementation of the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic structural diagram of an optical switching device provided in an embodiment of the present application;

[0025] FIG2 is an optical path diagram of a wavelength selective switch provided in an embodiment of the present application;

[0026] FIG3 is another optical path diagram of a wavelength selective switch provided in an embodiment of the present application;

[0027] FIG4 is a schematic diagram of the structure of an optical switching engine provided in an embodiment of the present application;

[0028] FIG5 is a schematic diagram of a partial structure of a wavelength selective switch provided in an embodiment of the present application;

[0029] FIG6 is a schematic diagram of a partial structure of a wavelength selective switch provided in an embodiment of the present application;

[0030] FIG7 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0031] FIG8 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0032] FIG9 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0033] FIG10 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0034] FIG11 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0035] FIG12 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0036] FIG13 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0037] FIG14 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0038] FIG15 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0039] FIG16 is a schematic diagram of a partial structure of another wavelength selective switch provided in an embodiment of the present application;

[0040] FIG17 is a schematic structural diagram of a wavelength selective switch provided in an embodiment of the present application;

[0041] FIG18 is a flow chart of a method for transmitting optical signals provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

[0043] The present application provides an optical network system, which includes multiple optical switching devices. The optical switching devices can exchange optical signals through optical fibers.

[0044] In some embodiments, the optical switching equipment can be devices capable of switching optical signals, such as ROADMs. ROADMs enable flexible service scheduling and intelligent O&M for all-optical networks, offering wavelength-level scheduling and multi-dimensional flexible networking capabilities. Introducing ROADMs into optical network systems allows operators to quickly provide wavelength-level services, facilitating network planning, reducing operating expenses, and simplifying and lowering maintenance costs.

[0045] For example, Figure 1 is a schematic diagram of the structure of a ROADM provided by an embodiment of the present application. As shown in Figure 1, the ROADM includes multiple boards, some of which are located on the line side in Figure 1, and others on the client side in Figure 1. A board on the client side connects a transmitter (TX) and a receiver (RX). The boards can also implement optical switching. The ROADM utilizes multiple boards to exchange light, thus achieving optical switching in the ROADM.

[0046] A single board includes at least one wavelength selective switch (WSS). Figure 1 illustrates a single board including multiple WSSs. Some WSSs have one input port and N output ports (expressed as 1×N, where N>1), or some WSSs have M input ports and N output ports (expressed as M×N, where M>1, where N>1). A WSS can combine single-wavelength optical signals from multiple input ports (also known as demultiplexing ports) into a multi-wavelength optical signal (such as a wavelength-division multiplexed (WDM) signal) and transmit the multi-wavelength optical signal to a single output port (also known as a multiplexing port). In addition to at least one WSS, a single board may also include other components, which are not listed here.

[0047] By connecting the ports of multiple wavelength selective switches, ROADM can transmit an optical signal of any wavelength at any input port of the ROADM to any output port of the ROADM.

[0048] In some embodiments, the optical switching device may also be a device different from the ROADM, and the number of boards in the device (>1) is different from the number of boards in the ROADM, and / or the connection relationship between the boards in the device is different from the connection relationship between the boards in the ROADM. Therefore, the optical switching device provided in the present application may include multiple boards, and there is a connection relationship between these boards. Through the connection between the boards, optical switching of the optical switching device can be achieved. In addition to including multiple boards, the optical switching device may also include other components. For example, the optical switching device also includes a power module, a heat dissipation module, etc. The power module is used to supply power to the board, and the heat dissipation module is used to dissipate heat from the board.

[0049] As can be seen from the above, the wavelength selective switch is an important component of a single board, optical switching equipment, and optical switching system. The following will further introduce the structure of the wavelength selective switch with reference to Figure 2.

[0050] For example, Figure 2(a) or Figure 3(a) is an optical path diagram of a wavelength selective switch in the port direction x provided by an embodiment of the present application, and the orthographic projection of the transmission path of the optical signal between the ports of the wavelength selective switch on the reference plane xz is the optical path diagram shown in Figure 2(a) and Figure 3(a). Among them, the orthographic projections of the multiple ports of the wavelength selective switch in the reference plane xz can be arranged in sequence along the port direction x. The arrangement direction of the multiple ports can be the port direction x, or can be different from the port direction x, and this application does not limit this. The orthographic projection of the transmission path on the reference plane xz refers to: when light perpendicular to the reference plane xz is irradiated from the side of the transmission path away from the reference plane xz to the reference plane xz, the projection of the transmission path on the reference plane xz is formed.

[0051] The reference plane xz is perpendicular to the dispersion direction y. For example, Figures 2(b) and 3(b) are optical path diagrams of the wavelength selective switch provided in an embodiment of the present application in the dispersion direction y. For multiple first single-wavelength optical signals input from multiple first input ports (such as I1, I2, and I3 in the figure) included in the wavelength selective switch, the projection of the transmission paths of the multiple first single-wavelength optical signals in the dispersion direction y on the reference plane yz is shown in Figure 2(b).

[0052] 2(a) and (b), the multiple first input ports (such as I1, I2, and I3 in the figure) input multiple first single-wavelength optical signals to the first optical switching engine. The first optical switching engine deflects the multiple first single-wavelength optical signals by a first angle and transmits them to the dispersion module. The dispersion module transmits the multiple first single-wavelength optical signals to multiple positions of the second optical switching engine along the dispersion direction y (such as positions L1, L2, and L3 in Figures 2(b) and 3(b)). The multiple first single-wavelength optical signals are reflected back to the dispersion module at these multiple positions.

[0053] 3(a) and (b), the multiple first input ports (e.g., I1, I2, and I3) of the wavelength selective switch correspond to a first output port (e.g., O1). The dispersion module combines the multiple first single-wavelength optical signals into a multi-wavelength optical signal and transmits the multi-wavelength optical signal to the first output port.

[0054] The wavelength selective switch can realize the attenuation function of signal power.

[0055] To achieve signal power attenuation, the wavelength selective switch includes multiple output ports. Assuming the multiple output ports include a first output port O1 and a second output port O2, the wavelength selective switch includes multiple first input ports (I1, I2, and I3 in the figure) corresponding to the first output port O1 and multiple second input ports (not shown) corresponding to the second output port O2. Referring to Figure 4 , the second optical switching engine includes a row of sub-areas corresponding to the first output port O1 and a row of sub-areas corresponding to the second output port O2. The row of sub-areas corresponding to the first output port O1 and the row of sub-areas corresponding to the second output port O2 are adjacent. The row of sub-areas corresponding to the first output port O1 includes multiple first sub-areas, and the row of sub-areas corresponding to the second output port O2 includes multiple second sub-areas.

[0056] Referring to Figure 2 , multiple first input ports (I1, I2, and I3) input multiple first single-wavelength optical signals into a first optical switching engine. Each first single-wavelength optical signal includes a first portion and a second portion. The first optical switching engine deflects the multiple first single-wavelength optical signals by a first angle and transmits them to a dispersion module. The dispersion module transmits the first portions of the multiple first single-wavelength optical signals deflected by the first angle to multiple first sub-regions of a second optical switching engine, and transmits the second portions of the multiple first single-wavelength optical signals deflected by the first angle to multiple second sub-regions of the first optical switching engine.

[0057] As shown in Figure 3, the first portion of the multiple first single-wavelength optical signals, after being deflected at the first angle, is reflected back to the dispersion module at the multiple first sub-areas. The second portion of the multiple first single-wavelength optical signals, after being deflected at the first angle, is reflected back to the dispersion module at the multiple second sub-areas. The dispersion module combines the reflected first portions of the multiple first single-wavelength optical signals into a single multi-wavelength optical signal and transmits this multi-wavelength optical signal to the first output port O1, thereby achieving signal power attenuation.

[0058] The dispersion module combines the reflected second portions of the multiple first single-wavelength optical signals into another multi-wavelength optical signal and transmits this second multi-wavelength optical signal to the second output port O2. This causes signal crosstalk between this second multi-wavelength optical signal and the multi-wavelength optical signal at the second output port O2. Therefore, when the wavelength selective switch implements the signal power attenuation function, signal crosstalk may also occur.

[0059] To solve the above problem, referring to FIG. 5 and FIG. 6 , an embodiment of the present application provides a wavelength selective switch 500 , which includes:

[0060] The first output port O1a, multiple first input ports corresponding to the first output port O1a (as shown in FIG5 , I1a, I2a, and I3a), the first optical switching engine 2, the dispersion module 3, and the second optical switching engine 4. The second optical switching engine 4 includes a first region 41 and a second region 42, the first region 41 and the second region 42 being adjacent to each other. The first region 41 includes multiple first sub-regions 411 corresponding to the first output port O1a, and the width of the second region is greater than or equal to 2.5 times the optical spot size.

[0061] 5 , a plurality of first input ports (I1a, I2a, and I3a as shown in FIG5 ) are configured to transmit a plurality of first single-wavelength optical signals to the first optical switching engine 2 , each of the first single-wavelength optical signals including a first portion and a second portion;

[0062] The first optical switching engine 2 is configured to deflect the plurality of first single-wavelength optical signals by a first angle and transmit the signals to the dispersion module 3;

[0063] The dispersion module 3 is configured to transmit a first portion of the plurality of first single-wavelength optical signals after being deflected at the first angle to the plurality of first sub-regions 411, and transmit a second portion of the plurality of first single-wavelength optical signals after being deflected at the first angle to the second region 42. Referring to FIG. 6 , the first portion of the plurality of first single-wavelength optical signals after being deflected at the first angle is reflected back to the dispersion module 3 from the plurality of first sub-regions 411, and the spot size of the light is equal to the spot size of each first single-wavelength optical signal in the port direction.

[0064] The dispersion module 3 is further configured to combine the first portion of the reflected multiple first single-wavelength optical signals into a first multi-wavelength optical signal, and transmit the first multi-wavelength optical signal to the first output port (O1a as shown in FIG6 ).

[0065] In some embodiments, the plurality of first single-wavelength optical signals are signals received by the plurality of first input ports.

[0066] In some embodiments, the first angle is constrained by the positions of the plurality of first sub-regions 411 and the position of the second region 42 .

[0067] For the first portion of the multiple first single-wavelength optical signals transmitted to the multiple first sub-areas 411, the multiple first sub-areas 411 may reflect the first portion of the multiple first single-wavelength optical signals toward the dispersion module 3. However, for the second portion of the multiple first single-wavelength optical signals transmitted to the second area 42, the second area 42 may not reflect the second portion of the multiple first single-wavelength optical signals.

[0068] Because the multiple first sub-regions 411 reflect the first parts of the multiple first single-wavelength optical signals back to the dispersion module 3, the dispersion module 3 combines the first parts of the multiple first single-wavelength optical signals into a first multi-wavelength optical signal. In this way, the power of the first multi-wavelength optical signal is less than the sum of the powers of the multiple first single-wavelength optical signals. The first multi-wavelength optical signal is transmitted to the first output port, thereby achieving a signal power attenuation function.

[0069] Because the width of the second region 42 is greater than or equal to 2.5 times the optical spot size, the dispersion module 3 can allow the second portions of the multiple first single-wavelength optical signals to fall within the second region 42, while the second region 42 does not reflect the second portions of the multiple first single-wavelength optical signals toward the dispersion module 3. Therefore, for output ports other than the first output port O1a of the wavelength selective switch 500, the dispersion module 3 does not transmit the multi-wavelength optical signal formed by combining the second portions of the multiple first single-wavelength optical signals to the other output ports, thereby preventing crosstalk with the multi-wavelength optical signals on the other output ports.

[0070] For each first sub-region 411 in the first region 41 , the dispersion module 3 may transmit a first portion of a first single-wavelength optical signal to the first sub-region 411 , and the first sub-region 411 reflects the first portion of the first single-wavelength optical signal back to the dispersion module 3 .

[0071] In some embodiments, each of the plurality of first single-wavelength optical signals has a different wavelength.

[0072] 5 or 6 , the first output port O1a corresponds to the first area 41 and the second area 42 in the second optical switching engine 4. Similarly, the wavelength selective switch 500 may also include other output ports, and the second optical switching engine 4 may also include two areas corresponding to the other output ports, wherein the structure of one area is the same as that of the first area 41, and the structure of the other area is the same as that of the second area 42.

[0073] For example, referring to FIG. 5 or FIG. 6 , the wavelength selective switch 500 further includes a second output port O2a and multiple second input ports (I4a and I5a, as shown in FIG. 5 ) corresponding to the second output port O2a. The second optical switching engine 4 further includes a third region 43 and a fourth region 44 corresponding to the second output port O2a. The third region 43 includes multiple second sub-regions 431 corresponding to the second output port O2a. The width of the fourth region 44 is greater than or equal to 2.5 times the optical spot size.

[0074] The plurality of second input ports (I4a, I5a) are used to transmit a plurality of second single-wavelength optical signals (not shown) to the first optical switching engine 2, each second single-wavelength optical signal including a third portion and a fourth portion;

[0075] The first optical switching engine 2 is further configured to deflect the plurality of second single-wavelength optical signals by a fifth angle and transmit the deflected signals to the dispersion module 3, wherein the first angle and the fifth angle are different.

[0076] The dispersion module 3 is further configured to transmit the third portion of the plurality of second single-wavelength optical signals after being deflected at the fifth angle to the plurality of second sub-areas 431, transmit the fourth portion of the plurality of second single-wavelength optical signals after being deflected at the fifth angle to the fourth area 44, and reflect the third portion of the plurality of second single-wavelength optical signals after being deflected at the fifth angle back to the dispersion module 3 at the plurality of second sub-areas 431;

[0077] The dispersion module 3 is further configured to combine the third portion of the reflected second single-wavelength optical signals into a second multi-wavelength optical signal, and transmit the second multi-wavelength optical signal to the second output port (O2a as shown in FIG6 ).

[0078] In some embodiments, the fifth angle is constrained by the positions of the plurality of second sub-regions 431 and the position of the fourth region 44 .

[0079] In some embodiments, each second single-wavelength optical signal in the plurality of second single-wavelength optical signals has a different wavelength.

[0080] For the wavelength selective switch 500 of the structure shown in Figures 5 and 6, each output port in the wavelength selective switch 500 corresponds to two areas, such as the first output port O1a corresponds to the first area 41 and the second area 42, and the second output port O2a corresponds to the third area 43 and the fourth area 44. This will increase the size of the second optical switching engine 4.

[0081] In order to reduce the size of the second optical switching engine 4, the first output port O1a and the second output port O2a can share the second area 42. Referring to Figures 7 and 8, the third area 43 and the second area 42 included in the second optical switching engine 4 are adjacent to each other, and the second area 42 is located between the first area 41 and the third area 43. The third area 43 includes multiple second sub-areas 431 corresponding to the second output port O2a.

[0082] 7 , the plurality of second input ports (I4a, I5a as shown in FIG7 ) are configured to transmit a plurality of second single-wavelength optical signals to the first optical switching engine 2 , each second single-wavelength optical signal including a third portion and a fourth portion;

[0083] The first optical switching engine 2 is further configured to deflect the plurality of second single-wavelength optical signals by a second angle and transmit the signals to the dispersion module 3;

[0084] The dispersion module 3 is further configured to transmit a third portion of the plurality of second single-wavelength optical signals after being deflected at the second angle to the plurality of second sub-areas 431, and to transmit a fourth portion of the plurality of second single-wavelength optical signals after being deflected at the second angle to the second area 42. Referring to FIG. 8 , the third portion of the plurality of second single-wavelength optical signals is reflected back to the dispersion module 3 by the plurality of second sub-areas 431.

[0085] The dispersion module 3 is further configured to combine the third portion of the reflected second single-wavelength optical signals into a second multi-wavelength optical signal, and transmit the second multi-wavelength optical signal to the second output port (O2a as shown in FIG8 ).

[0086] Since the first output port O1a and the second output port O2a share the second area 42, the number of second areas 42 included in the second optical switching engine 4 can be reduced, thereby improving the space utilization of the second optical switching engine 4 and reducing the size of the second optical switching engine 4.

[0087] In some embodiments, the second angle is constrained by the positions of the plurality of second sub-regions 431 and the position of the second region 42 .

[0088] For the third portion of the plurality of second single-wavelength optical signals transmitted to the plurality of second sub-regions 431, the plurality of second sub-regions 431 may reflect the third portion of the plurality of second single-wavelength optical signals toward the dispersion module 3. However, for the fourth portion of the plurality of second single-wavelength optical signals transmitted to the second region 42, the second region may not reflect the fourth portion of the plurality of second single-wavelength optical signals.

[0089] Because the multiple second sub-regions 431 reflect the third portions of the multiple second single-wavelength optical signals back to the dispersion module 3, the dispersion module 3 combines the third portions of the multiple second single-wavelength optical signals into a second multi-wavelength optical signal. In this way, the power of the second multi-wavelength optical signal is less than the sum of the powers of the multiple second single-wavelength optical signals. The second multi-wavelength optical signal is transmitted to the second output port, thereby achieving a signal power attenuation function.

[0090] Because the width of the second region is greater than or equal to 2.5 times the spot size, the dispersion module 3 can cause the fourth portions of the multiple second single-wavelength optical signals to fall within the second region, and the second region does not reflect the fourth portions of the multiple second single-wavelength optical signals toward the dispersion module 3. In this way, for output ports other than the second output port included in the wavelength selective switch 500, the dispersion module 3 does not transmit the fourth portions of the multiple second single-wavelength optical signals to the other output ports, thereby preventing crosstalk with the multi-wavelength optical signals on the other output ports.

[0091] Referring to FIG. 7 or FIG. 8 , the first output port O1a and the second output port O2a correspond to the first region 41, the second region 42, and the third region 43 in the second optical switching engine 4. Similarly, the wavelength selective switch 500 may also include two other adjacent output ports, and the second optical switching engine 4 may also include three regions corresponding to the other two adjacent output ports. The structures of these three regions are the same as those of the first region 41, the second region 42, and the third region 43 described above. This allows the two adjacent output ports to share the second region 42, thereby reducing the size of the second optical switching engine 4.

[0092] In some embodiments, referring to FIG. 5 to FIG. 8 , the wavelength selective switch 500 further includes a first lens 51 , a second lens 52 and a separation component 53 . The first lens 51 and the second lens 52 form a 4f optical path.

[0093] 5 and 7 , the plurality of first input ports (such as I1a, I2a, and I3a as shown in FIG. 5 or FIG. 7 ) are configured to transmit a plurality of first single-wavelength optical signals to the first optical switching engine 2 ;

[0094] The first optical switching engine 2 is configured to deflect the plurality of first single-wavelength optical signals by a first angle and transmit the signals to the separation component 53;

[0095] a separation component 53, configured to deflect the plurality of first single-wavelength optical signals deflected at the first angle to the second lens 52;

[0096] The second lens 52 is used to transmit the multiple first single-wavelength optical signals deflected by the separation component 53 to the dispersion module 3 .

[0097] a dispersion module 3 configured to transmit a first portion of the plurality of first single-wavelength optical signals transmitted through the second lens 52 to the plurality of first sub-regions 411, and transmit a second portion of the plurality of first single-wavelength optical signals transmitted through the second lens 52 to the second region 42, wherein the first portion of the plurality of first single-wavelength optical signals transmitted through the second lens 52 is reflected back to the dispersion module 3 at the plurality of first sub-regions 411;

[0098] 6 or 8 , the dispersion module 3 is further configured to combine a first portion of the multiple first single-wavelength optical signals reflected by the multiple first sub-regions 411 into a first multi-wavelength optical signal, and transmit the first multi-wavelength optical signal to the second lens 52 ;

[0099] The second lens 52 is further used to transmit the first multi-wavelength optical signal to the first lens 51;

[0100] The first lens 51 is used to transmit the first multi-wavelength optical signal transmitted by the second lens 52 to the first output port (O1a as shown in FIG. 6 or FIG. 8 ).

[0101] Regarding the wavelength selective switch 500 shown in Figures 5 to 8 , since the second area 42 of the wavelength selective switch 500 does not reflect optical signals, the space utilization rate of the first optical switching engine 4 is low. To this end, the wavelength selective switch 500 can be designed as a twin structure, that is, the wavelength selective switch 500 can be a twin wavelength selective switch.

[0102] 9 and 10 , a twin-structured wavelength selective switch 500 includes a first port group and a second port group that are relatively arranged. The first port group includes the first output port O1a and a plurality of first input ports (as shown in FIG9 , I1a, I2a, and I3a). The second port group includes a third output port O1b and a plurality of third input ports corresponding to the third output port O1b (as shown in FIG9 , I1b, I2b, and I3b). The second region 42 includes a plurality of third sub-regions 421 corresponding to the third output port O1b. The wavelength selective switch 500 also includes a third optical switching engine 3.

[0103] 9 , the plurality of third input ports (I1b, I2b, I3b as shown in FIG9 ) are configured to transmit a plurality of third single-wavelength optical signals to the third optical switching engine 3 , each of the third single-wavelength optical signals including a fifth portion and a sixth portion;

[0104] The third optical switching engine 3 is configured to deflect the plurality of third single-wavelength optical signals by a third angle and transmit the deflected signals to the dispersion module 3;

[0105] The dispersion module 3 is further configured to transmit a fifth portion of the plurality of third single-wavelength optical signals deflected at a third angle to the plurality of third sub-regions 421, and to transmit a sixth portion of the at least one third single-wavelength optical signal to the at least one first sub-region 411, wherein the plurality of first sub-regions 411 include the at least one first sub-region 411, and the plurality of third single-wavelength optical signals deflected at the third angle include the at least one third single-wavelength optical signal. Referring to FIG. 10 , the fifth portion of the plurality of third single-wavelength optical signals is reflected back to the dispersion module 3 by the plurality of third sub-regions 421, and the sixth portion of the at least one third single-wavelength optical signal is reflected back to the dispersion module 3 by the at least one first sub-region 411.

[0106] The dispersion module 3 is further configured to combine the reflected fifth portions of the multiple third single-wavelength optical signals into a third multi-wavelength optical signal, and transmit the third multi-wavelength optical signal to a third output port (O1b as shown in FIG10 ); and to combine the reflected sixth portion of the at least one third single-wavelength optical signal into a fourth multi-wavelength optical signal, and transmit the fourth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch 500.

[0107] With respect to the multiple first single-wavelength optical signals transmitted by the first optical switching engine 2 to the dispersion module 3, the dispersion module 3 transmits the second portion of at least one of the multiple first single-wavelength optical signals to at least one third sub-region 421, which is included in the multiple third sub-regions 421. The second portion of the at least one first single-wavelength optical signal is reflected back to the dispersion module 3 by the at least one third sub-region 421. The dispersion module 3 combines the reflected second portions of the at least one first single-wavelength optical signal into a fifth multi-wavelength optical signal, and transmits the fifth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch 500.

[0108] Since the multiple first input ports (I1a, I2a, I3a as shown in FIG9 ) and the multiple third input ports (I1b, I2b, I3b as shown in FIG9 ) belong to different port groups, the wavelength of each first single-wavelength optical signal transmitted by the multiple first input ports is different from the wavelength of each third single-wavelength optical signal transmitted by the multiple third input ports. Thus, for each first sub-region 411 in the at least one first sub-region 411, the optical signal transmitted to the first sub-region 411 includes a first portion of a first single-wavelength optical signal and a sixth portion of a third single-wavelength optical signal. Because the wavelength of the first portion of the first single-wavelength optical signal is different from the wavelength of the sixth portion of the third single-wavelength optical signal, the dispersion module 3 transmits the first multi-wavelength optical signal in a different direction from the fourth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch 500.

[0109] Similarly, for each third sub-region 421 in the at least one third sub-region 421, the optical signal transmitted to the third sub-region 421 includes the second portion of a first single-wavelength optical signal and the fifth portion of a third single-wavelength optical signal. Because the wavelength of the second portion of the first single-wavelength optical signal is different from the wavelength of the fifth portion of the third single-wavelength optical signal, the dispersion module 3 transmits the third multi-wavelength optical signal in a different direction than the fifth multi-wavelength optical signal, combining the second portions of the first single-wavelength optical signals reflected by the plurality of third sub-regions 421 and the third multi-wavelength optical signal combined by the dispersion module 3. Specifically, the dispersion module 3 transmits the third multi-wavelength optical signal to the third output port O1b and transmits the combined fifth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch 500. This achieves signal power attenuation while avoiding signal crosstalk.

[0110] In some embodiments, the third angle is constrained by the position of the at least one first sub-region 411 and the positions of the plurality of third sub-regions 421 .

[0111] In some embodiments, the first optical switching engine 2 and the third optical switching engine 6 may be integrated together, or may be two different components.

[0112] In some embodiments, each of the plurality of third single-wavelength optical signals has a different wavelength.

[0113] In some embodiments, the first port group includes a column of input ports and a column of output ports, the column of input ports includes the above-mentioned multiple first input ports and multiple second input ports, and the column of output ports includes the above-mentioned first output port and second output port. The column of input ports and the column of output ports may be located in different columns or in the same column.

[0114] In some embodiments, the second port group includes a column of input ports and a column of output ports, the column of input ports includes the above-mentioned multiple third input ports, and the column of output ports includes the above-mentioned third output ports. The column of input ports and the column of output ports may be located in different columns or in the same column.

[0115] In some embodiments, a first offset between the center of the i-th first sub-region and the center of the i-th third sub-region in the dispersion direction is constrained by the spacing between the first port group and the second port group, where i=1, 2, 3, ..., K, where K is the number of the plurality of first sub-regions 411. The first offset between the center of the i-th first sub-region and the center of the i-th third sub-region in the dispersion direction is directly proportional to the spacing between the first port group and the second port group.

[0116] In some embodiments, referring to Figures 11 and 12 , the second output port O2a and multiple second input ports (such as I4a and I5a shown in Figure 11 ) also belong to the first port group, and the third region 43 of the second optical switching engine 4 includes multiple second sub-regions 431 corresponding to the second output port O2a. The multiple second sub-regions 431 in the third region 43 are sub-regions corresponding to the second output port O2a in the first port group.

[0117] Therefore, for any two adjacent rows of sub-areas in the second optical switching engine 4, one row of sub-areas contains multiple sub-areas corresponding to one output port in the first port group, and the other row of sub-areas contains multiple sub-areas corresponding to one output port in the second port group. For example, in the second optical switching engine 4 shown in Figures 11 or 12 , a row of first sub-areas 411 in the first area 41 contains multiple sub-areas corresponding to the first output port O1a in the first port group, a row of third sub-areas 421 in the second area 42 contains multiple sub-areas corresponding to the first output port O1b in the second port group, and a row of second sub-areas 431 in the third area 43 contains multiple sub-areas corresponding to the second output port O2a in the first port group.

[0118] The dispersion module 3 may not transmit the sixth portion of the third single-wavelength optical signal to the second area 42, but may transmit the sixth portion of the third single-wavelength optical signal to the third area 43. That is, for the first single-wavelength optical signal, the dispersion module 3 transmits the first portion of the first single-wavelength optical signal to the first sub-area 411 in the first area 41, and transmits the second portion of the first single-wavelength optical signal to the third sub-area 421 in the second area 42. For the third single-wavelength optical signal, the dispersion module 3 transmits the fifth portion of the third single-wavelength optical signal to the third sub-area 421 in the second area 42, and transmits the sixth portion of the third single-wavelength optical signal to the second sub-area 431 in the third area 43. In implementation,

[0119] 11 , the plurality of third input ports (I1b, I2b, I3b as shown in FIG11 ) are used for the third optical switching engine 6 to transmit a plurality of third single-wavelength optical signals, each of which includes a fifth portion and a sixth portion.

[0120] a third optical switching engine 6, configured to deflect the plurality of third single-wavelength optical signals by a fourth angle and transmit the deflected signals to the dispersion module 3, wherein the first angle and the fourth angle are different;

[0121] The dispersion module 3 is further configured to transmit a fifth portion of the plurality of third single-wavelength optical signals deflected at a fourth angle to the plurality of third sub-regions 421, and to transmit a sixth portion of the at least one third single-wavelength optical signal to the at least one second sub-region 431, wherein the plurality of second sub-regions 431 include the at least one second sub-region 431, and the plurality of third single-wavelength optical signals deflected at the fourth angle include the at least one third single-wavelength optical signal. Referring to FIG. 12 , the fifth portion of the plurality of third single-wavelength optical signals is reflected back to the dispersion module 3 by the plurality of third sub-regions 421, and the sixth portion of the at least one third single-wavelength optical signal is reflected back to the dispersion module 3 by the at least one second sub-region 431.

[0122] The dispersion module 3 is further configured to combine a fifth portion of the multiple third single-wavelength optical signals reflected by the multiple third sub-regions 421 into a third multi-wavelength optical signal, and transmit the third multi-wavelength optical signal to the third output port; and to combine a sixth portion of the at least one third single-wavelength optical signal reflected by the at least one second sub-region 431 into a fourth multi-wavelength optical signal, and transmit the fourth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch 500.

[0123] In some embodiments, the fourth angle is constrained by positions of the plurality of third sub-regions 421 and a position of the at least one second sub-region 431 .

[0124] Regarding the multiple first single-wavelength optical signals deflected by the first angle that are transmitted by the first optical switching engine 2 to the dispersion module 3, the dispersion module 3 still transmits the first portion of the multiple first single-wavelength optical signals deflected by the first angle to the multiple first sub-areas 411, and transmits the second portion of at least one first single-wavelength optical signal deflected by the first angle to the at least one third sub-area 421; wherein, the first portion of the multiple first single-wavelength optical signals deflected by the first angle are reflected back to the dispersion module 3 from the multiple first sub-areas 411, and the second portion of at least one first single-wavelength optical signal deflected by the first angle are reflected back to the dispersion module 3 from the at least one second sub-area 421.

[0125] Then, the dispersion module 3 combines the first parts of the multiple first single-wavelength optical signals reflected by the multiple first sub-regions 411 into a first multi-wavelength optical signal, and transmits the first multi-wavelength optical signal to the first output port. It also combines the second part of the at least one first single-wavelength optical signal reflected by the at least one third sub-region 421 into a fifth multi-wavelength optical signal, and transmits the fifth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch 500.

[0126] In the second optical switching engine 4, a row of sub-areas (including multiple sub-areas) corresponding to other output ports in the first port group and a row of sub-areas (including multiple sub-areas) corresponding to other output ports in the second port group are arranged alternately, just like a row of first sub-areas 411 corresponding to the first output port and a row of third sub-areas 421 corresponding to the third output port.

[0127] In some embodiments, in addition to corresponding to multiple first input ports, the first output port O1a can also correspond to at least one fourth input port. The wavelength selection switch 500 does not need to attenuate the first single-wavelength optical signal input by the at least one fourth input port. The first area 41 of the second optical switching engine 4 also includes at least one first sub-area 411.

[0128] That is, the at least one fourth input port is used to transmit at least one first single-wavelength optical signal to the first optical switching engine 2;

[0129] The first optical switching engine 2 is further configured to deflect the at least one first single-wavelength optical signal by a fifth angle and transmit the deflected signal to the dispersion module 3, where the fifth angle is different from the first angle.

[0130] The dispersion module 3 is further configured to transmit the at least one first single-wavelength optical signal deflected at the fifth angle to the at least one first sub-region 411; wherein the at least one first single-wavelength optical signal deflected at the fifth angle is reflected back to the dispersion module 3 on the at least one first sub-region 411;

[0131] The dispersion module 3 is further configured to combine the at least one reflected first single-wavelength optical signal into a sixth multi-wavelength optical signal, and transmit the sixth multi-wavelength optical signal to the first output port.

[0132] In some embodiments, the fifth angle is constrained by the position of the at least one first sub-region 411 .

[0133] In some embodiments, referring to FIG13 , the wavelength selective switch 500 further includes a beam combiner 55 and a deflection unit 56 ;

[0134] The first optical switching engine 2 is configured to deflect the plurality of first single-wavelength optical signals by a first angle and transmit the plurality of first single-wavelength optical signals deflected by the first angle to the beam combiner 55;

[0135] The third optical switching engine 6 is configured to transmit the third single-wavelength optical signals deflected at the third angle or the fourth angle to the deflection unit 56 after deflecting the plurality of third single-wavelength optical signals at the third angle or the fourth angle;

[0136] a deflection unit 56 , configured to deflect the plurality of third single-wavelength optical signals transmitted by the third optical switching engine 6 to the beam combiner 55 ;

[0137] The beam combiner 55 is configured to transmit the multiple first single-wavelength optical signals transmitted by the first optical switching engine 2 and the multiple third single-wavelength optical signals deflected by the deflection unit 56 to the dispersion module 3 .

[0138] This can reduce the second offset in the dispersion direction between the i-th first single-wavelength optical signal and the i-th third single-wavelength optical signal transmitted to the dispersion module 3. The second offset is directly proportional to the first offset in the dispersion direction between the center of the i-th first sub-region and the center of the i-th third sub-region, where i = 1, 2, 3, ..., K. Therefore, the smaller the second offset, the smaller the first offset, thereby reducing the width of the second optical switching engine 4.

[0139] Optionally, the second offset may be 0 or slightly greater than 0, so that the first offset may also be 0 or slightly greater than 0.

[0140] In some embodiments, the beam combiner 55 and the deflection unit 56 can be integrated together, or can be two different components.

[0141] In some embodiments, referring to FIG. 13 and FIG. 14 , the wavelength selective switch 500 further includes: a third lens 57 and a fourth lens 58 ; the beam combiner 55 is located between the second lens 52 and the dispersion module 3 ; and the deflection unit 56 is located between the fourth lens 58 and the dispersion module 3 .

[0142] 13 , the first optical switching engine 2 is configured to deflect the plurality of first single-wavelength optical signals by a first angle and then transmit the plurality of first single-wavelength optical signals deflected by the first angle to the separation component 53 ;

[0143] The third optical switching engine 6 is configured to transmit the plurality of third single-wavelength optical signals deflected at a third angle or a fourth angle to the separation component 53 after deflecting the plurality of third single-wavelength optical signals at a third angle or a fourth angle;

[0144] a separation component 53 for transmitting the plurality of first single-wavelength optical signals transmitted by the first optical switching engine 2 to the second lens 52 , and transmitting the plurality of third single-wavelength optical signals transmitted by the third optical switching engine 6 to the fourth lens 58 ;

[0145] The second lens 52 is used to transmit the multiple first single-wavelength optical signals transmitted by the separation component 53 to the beam combiner 55;

[0146] a fourth lens 58 for transmitting the plurality of third single-wavelength optical signals transmitted by the separation component 53 to the deflection unit 56;

[0147] a deflection unit 56 , configured to deflect the plurality of third single-wavelength optical signals transmitted through the fourth lens 58 to the beam combiner 55 ;

[0148] The beam combiner 55 is configured to transmit the multiple first single-wavelength optical signals transmitted through the second lens 52 and the multiple third single-wavelength optical signals transmitted through the fourth lens 58 to the dispersion module 3 .

[0149] 14 , the dispersion module 3 is configured to transmit the first multi-wavelength optical signal and the third multi-wavelength optical signal to the combiner 55 after merging the first multi-wavelength optical signal and the third multi-wavelength optical signal;

[0150] The beam combiner 55 is further configured to transmit the first multi-wavelength optical signal to the second lens 52 and transmit the third multi-wavelength optical signal to the deflection unit 56;

[0151] The first lens 51 and the second lens 52 form a 4f optical path. The second lens 52 is also used to transmit the first multi-wavelength optical signal transmitted through the combiner 55 to the first lens 51; then, the first lens 51 is used to transmit the first multi-wavelength optical signal transmitted through the second lens 52 to the first output port O1a.

[0152] The third lens 57 and the fourth lens 58 form another 4f optical path. The deflection unit 56 is further used to deflect the third multi-wavelength optical signal transmitted through the combiner 55 to the fourth lens 58; the fourth lens 58 is further used to transmit the third multi-wavelength optical signal deflected by the deflection unit 56 to the third lens 57; then, the third lens 57 is used to transmit the third multi-wavelength optical signal transmitted through the fourth lens 58 to the third output port O1b.

[0153] In some embodiments, referring to FIG14 and FIG15 , the beam combiner 55 may be located between the first lens 51 and the second lens 52 , so that the fourth lens 58 may be omitted to save costs.

[0154] 15 , the first optical switching engine 2 is configured to deflect the plurality of first single-wavelength optical signals by a first angle and then transmit the plurality of first single-wavelength optical signals deflected by the first angle to the separation component 53 ;

[0155] The third optical switching engine 6 is configured to transmit the plurality of third single-wavelength optical signals deflected at a third angle or a fourth angle to the separation component 53 after deflecting the plurality of third single-wavelength optical signals at a third angle or a fourth angle;

[0156] a separation component 53 for transmitting the plurality of first single-wavelength optical signals transmitted by the first optical switching engine 2 to the second lens 52 , and transmitting the plurality of third single-wavelength optical signals transmitted by the third optical switching engine 6 to the fourth lens 58 ;

[0157] The second lens 52 is used to transmit the multiple first single-wavelength optical signals transmitted by the separation component 53 to the beam combiner 55;

[0158] a fourth lens 58 for transmitting the plurality of third single-wavelength optical signals transmitted by the separation component 53 to the deflection unit 56;

[0159] a deflection unit 56 , configured to deflect the plurality of third single-wavelength optical signals transmitted through the fourth lens 58 to the beam combiner 55 ;

[0160] The beam combiner 55 is configured to transmit the multiple first single-wavelength optical signals transmitted through the second lens 52 and the multiple third single-wavelength optical signals transmitted through the fourth lens 58 to the dispersion module 3 .

[0161] 16 , the dispersion module 3 is configured to transmit the first multi-wavelength optical signal and the third multi-wavelength optical signal to the second lens 52 after merging the first multi-wavelength optical signal and the third multi-wavelength optical signal;

[0162] The second lens 52 is further used to transmit the first multi-wavelength optical signal and the third multi-wavelength optical signal to the beam combiner 55;

[0163] The beam combiner 55 is further configured to transmit the first multi-wavelength optical signal transmitted through the second lens 52 to the first lens 51 , and to transmit the third multi-wavelength optical signal transmitted through the second lens 52 to the deflection unit 56 ;

[0164] The first lens 51 is used to transmit the first multi-wavelength optical signal transmitted through the beam combiner 55 to the first output port O1a.

[0165] The deflection unit 56 is further configured to deflect the third multi-wavelength optical signal transmitted through the beam combiner 55 to the third lens 57 ;

[0166] The third lens 57 is used to transmit the third multi-wavelength optical signal transmitted through the beam combiner 55 to the third output port O1b.

[0167] In some embodiments, referring to Figures 9 to 16, the first offset of the center of the i-th first sub-region 411 and the center of the i-th third sub-region 421 in the dispersion direction is greater than or equal to 0 and less than or equal to the sum of the widths of 10 first sub-regions 411, i = 1, 2, 3,...

[0168] For example, referring to FIG. 9 to FIG. 12 , a first offset between the center of the i-th first sub-region 411 and the center of the i-th third sub-region 421 in the dispersion direction is equal to the width of one first sub-region 411 .

[0169] Assume that the number of the multiple first single-wavelength optical signals received by the dispersion module 3 is Q, where Q is an integer greater than or equal to 3, and the number of the multiple first sub-regions 411 and the number of the multiple third sub-regions 421 are both Q. The dispersion module 3 transmits the first parts of the Q first single-wavelength optical signals to the Q first sub-regions 411, and transmits the second parts of the Q-2 first single-wavelength optical signals to the Q-2 third sub-regions 421, where the Q-2 third sub-regions 421 are the 2nd to Q-1th third sub-regions 421.

[0170] For another example, referring to Figures 13 to 16 , a first offset in the dispersion direction between the center of the i-th first sub-region 411 and the center of the i-th third sub-region 421 is greater than or equal to 0 and less than half the width of one first sub-region 411. When the dispersion module 3 receives the plurality of first single-wavelength optical signals, the dispersion module 3 transmits a first portion of the plurality of first single-wavelength optical signals to the plurality of first sub-regions 411, and transmits a second portion of the plurality of first single-wavelength optical signals to the plurality of third sub-regions 421.

[0171] The dispersion module 3 may be a transmissive dispersion module 3 or a reflective dispersion module 3 .

[0172] In some embodiments, the dispersion module 3 is a transmissive dispersion module 3 . Referring to FIG. 5 to FIG. 16 , the dispersion module 3 includes a transmissive dispersion grating 31 , a fifth lens 32 , and a sixth lens 33 . The dispersion grating 31 is located between the fifth lens 32 and the sixth lens 33 .

[0173] The fifth lens 32 is located between the dispersion grating 31 and the second lens 52 , and the sixth lens 33 is located between the dispersion grating 31 and the first optical switching engine 4 .

[0174] The fifth lens 32 and the sixth lens 33 form a 4f optical path. The first optical switching engine 2 transmits the multiple first single-wavelength optical signals, after being deflected by the first angle, to the front focal plane of the fifth lens 32. The fifth lens 33 transmits the multiple first single-wavelength optical signals to the dispersion grating 31. The dispersion grating 31 transmits the first portion of the multiple first single-wavelength optical signals to the sixth lens 33, and transmits the second portion of the multiple first single-wavelength optical signals to the sixth lens 33. The sixth lens 33 transmits the first portion of the multiple first single-wavelength optical signals transmitted through the dispersion grating 31 to the multiple first sub-regions 411; and transmits the second portion of the multiple first single-wavelength optical signals transmitted through the dispersion grating 31 to the second region 42.

[0175] The first portions of the multiple first single-wavelength optical signals are reflected by the multiple first sub-regions 411 back to the sixth lens 33. The sixth lens 33 transmits the reflected first portions of the multiple first single-wavelength optical signals to the dispersion grating 31. The dispersion grating 31 combines the first portions of the multiple first single-wavelength optical signals transmitted through the sixth lens 33 into a first multi-wavelength optical signal and transmits the first multi-wavelength optical signal to the fifth lens 32. The fifth lens 32 transmits the first multi-wavelength optical signal to the second lens 52. The second lens 52 transmits the first multi-wavelength optical signal transmitted through the fifth lens 32 to the first lens 51. The first lens 51 then transmits the first multi-wavelength optical signal transmitted through the second lens to the first output port O1a.

[0176] In some embodiments, the dispersion module 3 is a reflective dispersion module 3 . Referring to FIG. 17 , the dispersion module 3 includes a reflective dispersion grating 31 and a curved mirror 34 .

[0177] 17( a ), a plurality of first input ports (such as I1a, I2a, and I3a as shown in FIG17( a )) are configured to transmit a plurality of first single-wavelength optical signals to the first optical switching engine 2;

[0178] The first optical switching engine 2 is configured to deflect the plurality of first single-wavelength optical signals by a first angle and transmit the signals to the separation component 53;

[0179] a separation component 53, configured to transmit the plurality of first single-wavelength optical signals deflected at the first angle to the second lens 52;

[0180] The second lens 52 is used to transmit the plurality of first single-wavelength optical signals transmitted by the separation component 53 to the curved mirror 34;

[0181] a curved mirror 34 for reflecting the plurality of first single-wavelength optical signals to the dispersion grating 31;

[0182] The dispersion grating 31 is used to reflect the multiple first single-wavelength optical signals back to the curved mirror 34;

[0183] The curved mirror 34 is also used to transmit the first part of the multiple first single-wavelength optical signals to the multiple first sub-areas 411 included in the second optical switching engine 4; and to transmit the second part of the multiple first single-wavelength optical signals to the second area 42 included in the second optical switching engine 4; see Figure 17(b), the first part of the multiple first single-wavelength optical signals is reflected back to the curved mirror 34 on the multiple first sub-areas 411.

[0184] 17( b ), the curved mirror 34 is further configured to reflect the first portion of the reflected multiple first single-wavelength optical signals to the dispersion grating 31 ;

[0185] The dispersion grating 31 is further configured to combine a first portion of the plurality of first single-wavelength optical signals reflected by the curved mirror 34 into a first multi-wavelength optical signal, and transmit the first multi-wavelength optical signal to the curved mirror 34;

[0186] The curved mirror 34 is also used to transmit the first multi-wavelength optical signal to the second lens 52;

[0187] The second lens 52 is further used to transmit the first multi-wavelength optical signal reflected by the curved mirror 34 to the first lens 51;

[0188] The first lens 51 is configured to transmit the first multi-wavelength optical signal transmitted through the second lens 52 and to the first output port O1a.

[0189] In an embodiment of the present application, a second optical switching engine includes a first region and a second region, the first region and the second region being adjacent. The first region includes multiple first sub-regions corresponding to the first output port, and the width of the second region is greater than or equal to 2.5 times the spot size. Multiple first input ports are configured to transmit multiple first single-wavelength optical signals to the first optical switching engine, each of which includes a first portion and a second portion. The first optical switching engine is configured to deflect the multiple first single-wavelength optical signals by a first angle and transmit them to a dispersion module. The dispersion module is configured to transmit the first portion of the multiple first single-wavelength optical signals deflected by the first angle to the multiple first sub-regions, and transmit the second portion of the multiple first single-wavelength optical signals deflected by the first angle to the second region. The first portion of the multiple first single-wavelength optical signals deflected by the first angle is reflected back to the dispersion module from the multiple first sub-regions, with the spot size equal to the spot size of each first single-wavelength optical signal in the direction of the port. The dispersion module is further configured to combine the reflected first portions of the multiple first single-wavelength optical signals into a first multi-wavelength optical signal and transmit the first multi-wavelength optical signal to the first output port. Because the width of the second region is greater than or equal to 2.5 times the spot size, which is equal to the spot size of each first single-wavelength optical signal in the port direction, the dispersion module transmits the second portion of the multiple first single-wavelength optical signals to the second region, and the second region does not reflect the second portion of the multiple first single-wavelength optical signals. As a result, the dispersion module does not combine the second portions of the multiple first single-wavelength optical signals into a single multi-wavelength optical signal. Specifically, the multi-wavelength optical signal is not transmitted to any output port of the wavelength selective switch other than the first output port, thereby avoiding signal crosstalk.

[0190] Referring to FIG18 , an embodiment of the present application provides a method 600 for transmitting an optical signal. The method 600 is applied to a wavelength selective switch, which may be the wavelength selective switch 500 in any of the embodiments of FIG5 to 17 , and includes: a first output port, multiple first input ports corresponding to the first output port, a first optical switching engine, a dispersion module, and a second optical switching engine. The second optical switching engine includes a first region and a second region, the first region and the second region being adjacent to each other, the first region including multiple first sub-regions corresponding to the first output port, and the width of the second region being greater than or equal to 2.5 times the optical spot size. The method 600 includes:

[0191] Step 601: The plurality of first input ports transmit a plurality of first single-wavelength optical signals to a first optical switching engine, where each first single-wavelength optical signal includes a first portion and a second portion.

[0192] Step 602: The first optical switching engine deflects the plurality of first single-wavelength optical signals by a first angle and transmits the deflected signals to a dispersion module.

[0193] Step 603: The dispersion module transmits the first portion of the multiple first single-wavelength optical signals after being deflected at the first angle to the multiple first sub-areas, and transmits the second portion of the multiple first single-wavelength optical signals after being deflected at the first angle to the second area. The first portion of the multiple first single-wavelength optical signals after being deflected at the first angle is reflected back to the dispersion module at the multiple first sub-areas, and the spot size is equal to the spot size of each first single-wavelength optical signal in the port direction.

[0194] Step 604: The dispersion module combines the reflected first portion of the multiple first single-wavelength optical signals into a first multi-wavelength optical signal, and transmits the first multi-wavelength optical signal to the first output port.

[0195] In some embodiments, the wavelength selective switch further comprises: a second output port and a plurality of second input ports corresponding to the second output port; the second optical switching engine further comprises a third region, the third region being adjacent to the second region, the second region being located between the first region and the third region, and the third region comprising a plurality of second sub-regions corresponding to the second output ports. The method 600 further comprises the following processes 11 to 14.

[0196] 11: The plurality of second input ports transmit a plurality of second single-wavelength optical signals to the first optical switching engine, where each second single-wavelength optical signal includes a third portion and a fourth portion.

[0197] 12: The first optical switching engine deflects the multiple second single-wavelength optical signals at a second angle and transmits the deflected signals to the dispersion module, where the first angle and the second angle are different.

[0198] 13: The dispersion module transmits the multiple second single-wavelength optical signals after being deflected at the second angle to the multiple second sub-areas, transmits the fourth part of the multiple second single-wavelength optical signals after being deflected at the second angle to the second area, and the third part of the multiple second single-wavelength optical signals after being deflected at the second angle is reflected back to the dispersion module at the multiple second sub-areas.

[0199] 14: The dispersion module combines the reflected third parts of the plurality of second single-wavelength optical signals into a second multi-wavelength optical signal, and transmits the second multi-wavelength optical signal to the second output port.

[0200] In some embodiments, the wavelength selective switch further comprises a third optical switching engine, a third output port, and multiple third input ports corresponding to the third output port, the first output port and the multiple first input ports belong to a first port group, the third output port and the multiple third input ports belong to a second port group, the first port group and the second port group are arranged relative to each other, and the second region includes multiple third sub-regions corresponding to the third output port. The method 600 further comprises the following processes 21 to 24.

[0201] 21: The plurality of third input ports transmit a plurality of third single-wavelength optical signals to the third optical switching engine, where each third single-wavelength optical signal includes a fifth portion and a sixth portion.

[0202] 22: The third optical switching engine deflects the plurality of third single-wavelength optical signals by a third angle and transmits the deflected signals to the dispersion module, where the first angle and the third angle are different.

[0203] 23: The dispersion module transmits the fifth portion of the multiple third single-wavelength optical signals after being deflected by the third angle to the multiple third sub-regions, and transmits the sixth portion of the at least one third single-wavelength optical signal to at least one first sub-region, where the multiple first sub-regions include the at least one first sub-region, and the multiple third single-wavelength optical signals after being deflected by the third angle include the at least one third single-wavelength optical signal. The fifth portion of the multiple third single-wavelength optical signals after being deflected by the third angle is reflected back to the dispersion module from the multiple third sub-regions, and the sixth portion of the at least one third single-wavelength optical signal is reflected back to the dispersion module from the at least one first sub-region.

[0204] 24: The dispersion module combines the fifth portion of the reflected multiple third single-wavelength optical signals into a third multi-wavelength optical signal, and transmits the third multi-wavelength optical signal to the third output port, and combines the sixth portion of the reflected at least one third single-wavelength optical signal into a fourth multi-wavelength optical signal, and transmits the fourth multi-wavelength optical signal in a direction other than the port included in the wavelength selective switch.

[0205] In an embodiment of the present application, a second optical switching engine includes a first region and a second region, the first region and the second region being adjacent. The first region includes multiple first sub-regions corresponding to the first output port, and the width of the second region is greater than or equal to 2.5 times the spot size. The dispersion module transmits the first portion of the received multiple first single-wavelength optical signals to the multiple first sub-regions and transmits the second portion of the multiple first single-wavelength optical signals to the second region. The first portion of the multiple first single-wavelength optical signals is reflected back to the dispersion module by the multiple first sub-regions. The dispersion module combines the reflected first portions of the multiple first single-wavelength optical signals into a first multi-wavelength optical signal and transmits the first multi-wavelength optical signal to the first output port. Because the width of the second region is greater than or equal to 2.5 times the spot size, the spot size is equal to the spot size of each first single-wavelength optical signal in the direction of the port. This ensures that the dispersion module transmits the second portion of the multiple first single-wavelength optical signals to the second region without reflecting the second portion of the multiple first single-wavelength optical signals, thereby avoiding signal crosstalk.

[0206] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, which may be a read-only memory, a disk, or an optical disk, etc.

[0207] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A wavelength selective switch, characterized in that: The wavelength selective switch comprises: a first output port, a plurality of first input ports corresponding to the first output port, a first optical switching engine, a dispersion module, and a second optical switching engine, wherein the second optical switching engine comprises a first area and a second area, the first area and the second area are adjacent, the first area comprises a plurality of first sub-areas corresponding to the first output port, and a width of the second area is greater than or equal to 2.5 times of a light spot size; The plurality of first input ports are used to transmit a plurality of first single-wavelength optical signals to the first optical switching engine, each of the first single-wavelength optical signals comprising a first part and a second part; The first optical switching engine is used to deflect the plurality of first single-wavelength optical signals by a first angle and transmit them to the dispersion module; The dispersion module is used to transmit the first part of the plurality of first single-wavelength optical signals after being deflected at a first angle to the plurality of first sub-areas, and transmit the second part of the plurality of first single-wavelength optical signals after being deflected at the first angle to the second area, and the first part of the plurality of first single-wavelength optical signals after being deflected at the first angle is reflected back to the dispersion module on the plurality of first sub-areas, and the spot size is equal to the spot size of each first single-wavelength optical signal in the port direction; The dispersion module is further configured to combine a first portion of the reflected first single-wavelength optical signals into a first multi-wavelength optical signal, and transmit the first multi-wavelength optical signal to the first output port.

2. The wavelength selective switch according to claim 1, characterized in that: The wavelength selective switch further includes: a second output port and a plurality of second input ports corresponding to the second output port, the second optical switching engine further includes a third area, the third area is adjacent to the second area, the second area is located between the first area and the third area, and the third area includes a plurality of second sub-areas corresponding to the second output port; The plurality of second input ports are used to transmit a plurality of second single-wavelength optical signals to the first optical switching engine, each second single-wavelength optical signal comprising a third part and a fourth part; The first optical switching engine is further used to transmit the plurality of second single-wavelength optical signals to the dispersion module after deflecting them at a second angle, wherein the first angle and the second angle are different; The dispersion module is used to transmit the third part of the plurality of second single-wavelength optical signals after being deflected at the second angle to the plurality of second sub-areas, transmit the fourth part of the plurality of second single-wavelength optical signals after being deflected at the second angle to the second area, and reflect the third part of the plurality of second single-wavelength optical signals after being deflected at the second angle back to the dispersion module on the plurality of second sub-areas; The dispersion module is further configured to combine the reflected third portion of the plurality of second single-wavelength optical signals into a second multi-wavelength optical signal, and transmit the second multi-wavelength optical signal to the second output port.

3. The wavelength selective switch according to claim 1, characterized in that: The wavelength selective switch further includes a third optical switching engine, a third output port, and a plurality of third input ports corresponding to the third output port, the first output port and the plurality of first input ports belong to a first port group, the third output port and the plurality of third input ports belong to a second port group, the first port group and the second port group are arranged opposite to each other, and the second area includes a plurality of third sub-areas corresponding to the third output port; The plurality of third input ports are used to transmit a plurality of third single-wavelength optical signals to the third optical switching engine, each of the third single-wavelength optical signals comprising a fifth portion and a sixth portion; The third optical switching engine is used to deflect the plurality of third single-wavelength optical signals by a third angle and transmit them to the dispersion module, wherein the first angle and the third angle are different; The dispersion module is configured to transmit the fifth part of the plurality of third single-wavelength optical signals deflected at a third angle to the plurality of third sub-regions, and transmit the sixth part of at least one third single-wavelength optical signal to at least one first sub-region, the plurality of first sub-regions including the at least one first sub-region, the plurality of third single-wavelength optical signals deflected at the third angle include the at least one third single-wavelength optical signal, the fifth part of the plurality of third single-wavelength optical signals deflected at the third angle is reflected back to the dispersion module on the plurality of third sub-regions, and the sixth part of the at least one third single-wavelength optical signal is reflected back to the dispersion module on the at least one first sub-region; The dispersion module is further configured to combine the fifth part of the plurality of third single-wavelength optical signals after reflection into a third multi-wavelength optical signal, and transmit the third multi-wavelength optical signal to the third output port, and to combine the sixth part of the at least one third single-wavelength optical signal after reflection into a fourth multi-wavelength optical signal, and transmit the fourth multi-wavelength optical signal to a direction other than the port included in the wavelength selective switch. light signal.

4. The wavelength selective switch according to claim 3, characterized in that: The first offset in the dispersion direction between the center of the i-th first sub-region and the center of the i-th third window is greater than or equal to 0 and less than or equal to the sum of the widths of 20 first sub-regions, i=1, 2, 3, ..., K, K is the number of the multiple first sub-regions.

5. The wavelength selective switch according to claim 3 or 4, characterized in that: The wavelength selective switch also includes a beam combiner and a deflection unit; The first optical switching engine is used to transmit the plurality of first single-wavelength optical signals deflected at a first angle to the beam combiner; The third optical switching engine is used to transmit the plurality of third single-wavelength optical signals deflected by a third angle to the deflection unit; The deflection unit is used to deflect the plurality of third single-wavelength optical signals transmitted by the third optical switching engine to the beam combiner; The beam combiner is used to transmit the multiple first single-wavelength optical signals transmitted by the first optical switching engine and the multiple third single-wavelength optical signals deflected by the deflection unit to the dispersion module.

6. The wavelength selective switch according to claim 5, characterized in that: The second offset in the dispersion direction between the i-th first single-wavelength optical signal and the i-th third single-wavelength optical signal transmitted by the combiner to the dispersion module is constrained by the first offset, and the first offset is the offset in the dispersion direction between the center of the i-th first sub-region and the center of the i-th third sub-region, i=1, 2, 3, ..., K, K is the number of the multiple first sub-regions.

7. The wavelength selective switch according to claim 5 or 6, characterized in that: The wavelength selective switch further comprises: a lens; The beam combiner is used to transmit the plurality of first single-wavelength optical signals transmitted by the first optical switching engine and the plurality of third single-wavelength optical signals deflected by the deflection unit to the lens; The lens is used to transmit the multiple first single-wavelength optical signals and the multiple third single-wavelength optical signals transmitted through the beam combiner to the dispersion module.

8. A method for transmitting an optical signal, characterized in that: The method is applied to a wavelength selective switch, the wavelength selective switch comprising: a first output port, a plurality of first input ports corresponding to the first output port, a first optical switching engine, a dispersion module, and a second optical switching engine, the second optical switching engine comprising a first area and a second area, the first area and the second area being adjacent, the first area comprising a plurality of first sub-areas corresponding to the first output port, the width of the second area being greater than or equal to 2.5 times the size of the light spot, the method comprising: The plurality of first input ports transmit a plurality of first single-wavelength optical signals to the first optical switching engine, each of the first single-wavelength optical signals comprising a first portion and a second portion; The first optical switching engine deflects the plurality of first single-wavelength optical signals by a first angle and transmits the signals to the dispersion module; The dispersion module transmits the first part of the plurality of first single-wavelength optical signals after being deflected at a first angle to the plurality of first sub-areas, transmits the second part of the plurality of first single-wavelength optical signals after being deflected at the first angle to the second area, and the first part of the plurality of first single-wavelength optical signals after being deflected at the first angle is reflected back to the dispersion module on the plurality of first sub-areas, and the spot size is equal to the spot size of each first single-wavelength optical signal in the port direction; The dispersion module combines the reflected first parts of the plurality of first single-wavelength optical signals into a first multi-wavelength optical signal, and transmits the first multi-wavelength optical signal to the first output port.

9. The method according to claim 8, characterized in that The wavelength selective switch further includes: a second output port and a plurality of second input ports corresponding to the second output port; the second optical switching engine further includes a third area, the third area is adjacent to the second area, the second area is located between the first area and the third area, and the third area includes a plurality of second sub-areas corresponding to the second output port; the method further includes: The plurality of second input ports transmit a plurality of second single-wavelength optical signals to the first optical switching engine, each second single-wavelength optical signal comprising a third portion and a fourth portion; The first optical switching engine deflects the plurality of second single-wavelength optical signals at a second angle and transmits the deflected signals to the dispersion module, wherein the first angle and the second angle are different; The dispersion module transmits the third part of the plurality of second single-wavelength optical signals after being deflected at a second angle to the plurality of second sub-areas, transmitting the fourth part of the plurality of second single-wavelength optical signals after being deflected at the second angle to the second area, and reflecting the third part of the plurality of second single-wavelength optical signals after being deflected at the second angle back to the dispersion module on the plurality of second sub-areas; The dispersion module combines the reflected third parts of the plurality of second single-wavelength optical signals into a second multi-wavelength optical signal, and transmits the second multi-wavelength optical signal to the second output port.

10. The method according to claim 8, characterized in that The wavelength selective switch further includes a third optical switching engine, a third output port, and a plurality of third input ports corresponding to the third output port, the first output port and the plurality of first input ports belong to a first port group, the third output port and the plurality of third input ports belong to a second port group, the first port group and the second port group are arranged opposite to each other, and the second area includes a plurality of third sub-areas corresponding to the third output port; The method further comprises: The plurality of third input ports transmit a plurality of third single-wavelength optical signals to the third optical switching engine, each of the third single-wavelength optical signals comprising a fifth portion and a sixth portion; The third optical switching engine deflects the plurality of third single-wavelength optical signals at a third angle and transmits the deflected signals to the dispersion module, wherein the first angle and the third angle are different; The dispersion module transmits the fifth part of the plurality of third single-wavelength optical signals deflected by a third angle to the plurality of third sub-regions, and transmits the sixth part of at least one third single-wavelength optical signal to at least one first sub-region, the plurality of first sub-regions include the at least one first sub-region, the plurality of third single-wavelength optical signals deflected by the third angle include the at least one third single-wavelength optical signal, the fifth part of the plurality of third single-wavelength optical signals deflected by the third angle is reflected back to the dispersion module on the plurality of third sub-regions, and the sixth part of the at least one third single-wavelength optical signal is reflected back to the dispersion module on the at least one first sub-region; The dispersion module combines the reflected fifth parts of the plurality of third single-wavelength optical signals into a third multi-wavelength optical signal, and transmits the third multi-wavelength optical signal to the third output port, and combines the reflected sixth part of the at least one third single-wavelength optical signal into a fourth multi-wavelength optical signal, and transmits the fourth multi-wavelength optical signal to a direction other than the port included in the wavelength selective switch.

11. A single board, characterized in that: include: At least one wavelength selective switch according to any one of claims 1 to 7.

12. An optical switching device, characterized in that: It comprises a plurality of single boards, at least one of the plurality of single boards being the single board according to claim 11.

13. The optical switching device according to claim 12, characterized in that: The optical switching device is a reconfigurable optical fork multiplexer.

14. An optical network system, characterized in that: include: A plurality of optical switching devices, at least one of the plurality of optical switching devices is the optical switching device according to claim 12 or 13.

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